<template>
  <div>
    <!-- 商品分类导航 -->
    <div class="type-nav">
      <div class="container">
       <div @mouseleave="indexRecovery" @mouseenter="showEnter">
          <h2 class="all">全部商品分类</h2>
          <!--过渡效果         -->
          <transition name="sort">
            <div class="sort" v-show="show"  @mouseleave="showLeave">
              <div class="all-sort-list2" @click="goSearch">
                <div class="item" v-for="(c1,index) in categoryList" :key="c1.categoryId"
                     :class="{cur:index==currentIndex}">
                  <h3 >
                    <!-- 渲染后 元素的属性名会自动转为小写 -->
                    <a @mouseenter="indexChange(index)" :data-categoryName="c1.categoryName" :data-category1Id="c1.categoryId" >{{ c1.categoryName }}</a>
                  </h3>
                  <!--二三级展示列表 -->
                  <div class="item-list clearfix" :style="{display:index==currentIndex?'block':'none'}">
                    <div class="subitem" v-for="(c2,index) in c1.categoryChild" :key="c2.categoryId">
                      <dl class="fore">
                        <dt>
                          <a :data-categoryName="c2.categoryName"
                             :data-category2Id="c2.categoryId">{{ c2.categoryName }}</a>
                        </dt>
                        <dd>
                          <em v-for="(c3,index) in c2.categoryChild" :key="c3.categoryId">
                            <a :data-categoryName="c3.categoryName"
                               :data-category3Id="c3.categoryId">{{ c3.categoryName }}</a>
                          </em>
                        </dd>
                      </dl>
                    </div>
                  </div>
                </div>
              </div>
            </div>
          </transition>
        </div>
        <nav class="nav">
          <a href="###">服装城</a>
          <a href="###">美妆馆</a>
          <a href="###">尚品汇超市</a>
          <a href="###">全球购</a>
          <a href="###">闪购</a>
          <a href="###">团购</a>
          <a href="###">有趣</a>
          <a href="###">秒杀</a>
        </nav>

      </div>
    </div>
  </div>
</template>

<script>
import {mapState} from "vuex";
//引入节流器，node_modules中自带
import throttle from "lodash/throttle"

export default {
  name: "TypeNav",
  data() {
    return {
      currentIndex: -1,
      show:true,
    }
  },
  mounted() {
    //除了在home页面，CategoryList不展示
    if(this.$route.path!=='/home'){
      this.show=false;
    }
  },
  computed: {
    ...mapState({
      categoryList: (state) => {
        return state.home.categoryList//.slice(0,16);
      }
    })
  },
  methods: {
    // indexChange(index){
    //   this.currentIndex=index;
    // },
    //节流器写法,频繁触发->少量触发，节流触发次数
    indexChange: throttle(function (index) {
      this.currentIndex = index;
    }, 50),
    indexRecovery() {
      this.currentIndex = -1;
    },
    goSearch(event) {
      //获取event事件的点击位置
      let element = event.target
      // console.log(element)
      let {
        //前端标签里的属性名自动转为小写，取值的时候得注意
        categoryname,
        category1id,
        category2id,
        category3id
      } = element.dataset
      console.log(categoryname, category1id, category2id, category3id)
      //整理路由跳转的参数
      if (categoryname) {
        let location = {name: 'search'}
        let query = {categoryName: categoryname}
        if (category1id) {
          query.category1Id = category1id
        } else if (category2id) {
          query.category2Id = category2id
        } else {
          query.category3Id = category3id
        }
        if(this.$route.params){
          location.query = query
          location.params=this.$route.params
          // console.log(location);
          this.$router.push(location);
        }
      }
    },
    //除了在home页面，鼠标悬浮显示categoryList
    showEnter(){
      if(this.$route.path!=='/home'){
        this.show=true;
      }
    },
    //除了在home页面，鼠标移走不显示categoryList
    showLeave(){
      if(this.$route.path!=='/home'){
        this.show=false;
      }
    }
  }
}
</script>

<style scoped lang="less">
.type-nav {
  border-bottom: 2px solid #e1251b;

  .container {
    width: 1200px;
    margin: 0 auto;
    display: flex;
    position: relative;

    .all {
      width: 210px;
      height: 45px;
      background-color: #e1251b;
      line-height: 45px;
      text-align: center;
      color: #fff;
      font-size: 14px;
      font-weight: bold;
    }

    .nav {
      a {
        height: 45px;
        margin: 0 22px;
        line-height: 45px;
        font-size: 16px;
        color: #333;
      }
    }

    .sort {
      position: absolute;
      left: 0;
      top: 45px;
      width: 210px;
      height: 461px;
      position: absolute;
      background: #fafafa;
      z-index: 999;

      .all-sort-list2 {
        .item {
          h3 {
            line-height: 28px;
            font-size: 14px;
            font-weight: 400;
            overflow: hidden;
            padding: 0 20px;
            margin: 0;

            a {
              color: #333;
            }
          }


          .item-list {
            position: absolute;
            width: 734px;
            min-height: 460px;
            background: #f7f7f7;
            left: 210px;
            border: 1px solid #ddd;
            top: 0;
            z-index: 9999 !important;

            .subitem {
              float: left;
              width: 650px;
              padding: 0 4px 0 8px;

              dl {
                border-top: 1px solid #eee;
                padding: 6px 0;
                overflow: hidden;
                zoom: 1;

                &.fore {
                  border-top: 0;
                }

                dt {
                  float: left;
                  width: 54px;
                  line-height: 22px;
                  text-align: right;
                  padding: 3px 6px 0 0;
                  font-weight: 700;
                }

                dd {
                  float: left;
                  width: 415px;
                  padding: 3px 0 0;
                  overflow: hidden;

                  em {
                    float: left;
                    height: 14px;
                    line-height: 14px;
                    padding: 0 8px;
                    margin-top: 5px;
                    border-left: 1px solid #ccc;
                  }
                }
              }
            }
          }

          //&:hover {
          //  .item-list {
          //    display: block;
          //  }
          //}
        }

        .cur {
          background: skyblue;
        }

        //.item:hover{
        //  background: skyblue;
        //}
      }
    }
    .sort-enter{
      height: 0px;
    }
    .sort-enter-to{
      height: 461px;
    }
    .sort-enter-active{
      transition: all 0.2s linear;
    }
  }
}
</style>